The field of the invention relates to receiving stations for receiving solid waste from trucks or other vehicles at a waste disposal facility.
Facilities for handling solid waste materials from residential and industrial sources have become increasingly important as landfills close and waste disposal sites become more difficult to locate. Such facilities are often equipped with systems for recycling certain items and incinerating much of the combustible waste materials. Incineration allows the production of steam which can be used for heating or the generation of electricity.
Solid waste facilities often include a number of stations where the solid waste is successively handled and treated. Solid waste is generally brought into a facility by trucks which deposit the waste at a receiving station. Alternatively, the waste may be dumped onto a receiving floor by trucks and transferred to the receiving station by a wheel loader, crane or equivalent means. Once deposited, the solid waste may be conveyed from the receiving station to a picking station where recyclable materials and/or materials unsuitable for subsequent shredding may be removed. The shreddable materials may then be conveyed to a shredder, where they are shredded to a size which can be readily combusted. Ferrous metals may be removed from the shredded waste material by a magnetic separator. The shredded waste material may then be conveyed to a boiler where it is combusted.
It is preferable to avoid compacting the solid waste material at the receiving station due to the difficulty of transporting such material, sorting through it for unacceptable items and then attempting to shred it. Since the receiving station is generally of pit-like configuration, and the waste material is commonly dropped into it by sanitation trucks, wheel loaders and the like, there is a tendency for the material to compact. Compaction occurs due to several causes, including but not necessarily limited to depth of storage, pit sidewall geometry (i.e. convergent), and downward compaction forces from a wheel loader.
One proposed solution to the compaction problem is the use of a live bottom pit for receiving and conveying solid waste material. One such construction is disclosed in U.S. Pat. No. 4,020,956, which discloses a pit including an endless conveyor positioned at the bottom thereof. The conveyor includes a horizontal section and an inclined section extending upwardly at an angle exceeding thirty-five degrees. The purpose of the patented construction is to shred off material from the bottom of the mass within the pit and transport the shredded mass to another station, such as a pulverizing station.
Another consideration in the design of receiving stations for solid waste materials is the safety of the operators of the vehicles which unload these materials into the pits. Barriers have conventionally been employed which will engage the tires of the vehicles prior to their reaching the edges of the pit. Such barriers if constructed high enough to stop a moving vehicle will usually allow only marginally sufficient clearance for the solid waste material to be dumped from the vehicle. In virtually all applications of vehicle barriers at dumping pits, spillage of waste on the vehicle maneuvering floor occurs and causes significant housekeeping problems.